Space vector PWM for common mode voltage reduction and neutral point voltage balancing in three-level converters

This paper proposes a new space vector pulse-width modulation (PWM) for common mode (CM) voltage reduction and neutral point (NP) voltage balancing in three-level converters. In case of unbalanced NP voltage, a group of the space vectors that increase or decrease the NP voltage is chosen to achieve the NP voltage balancing while the resultant CM voltage has not only the minimized amplitude but also the dominant low frequency. In case of NP voltage balancing, the only space vectors with the same CM voltage are used to completely eliminate the CM voltage variation. To show the feasibility of the proposed PWM method, the simulation results are presented.